Longitudinal comparison of diffusion tensor imaging parameters and neuropsychological measures following endoscopic third ventriculostomy for hydrocephalus

Abstract

The authors report the case of a 25-month-old boy who underwent endoscopic third ventriculostomy (ETV) for hydrocephalus resulting from aqueductal stenosis. The patient's recovery was monitored longitudinally and prospectively using MR diffusion tensor imaging (DTI) and formal neuropsychological testing. Despite minimal change in ventricle size, improvement in the DTI characteristics and neurodevelopmental trajectory was observed following ETV. These data support the use of DTI as a biomarker to assess therapeutic response in children undergoing surgical treatment for hydrocephalus. In the patient featured in this report, DTI appeared to provide more information regarding postoperative neurodevelopmental outcome than ventricle size alone.

Figure 1

Conventional neuroimaging in a 25-month-old boy with hydrocephalus resulting from aqueductal stenosis. Left: Preoperative axial CT scan showing enlargement of the lateral and third ventricles with a moderately sized fourth ventricle. Right: Preoperative sagittal T1-weighted MR image demonstrating proximal aqueductal narrowing. A giant cisterna magna was also observed.

Figure 2

Stable ventricular size following successful ETV. Preoperative (A) and 14 months post-ETV (B) T2-weighted MR images used to calculate the frontooccipital horn ratio, which was 0.59 for both the preoperative and postoperative scans. Postoperative sagittal cine phase-contrast CSF flow study (C) demonstrating flow through the ventriculostomy.

Figure 3

Recovery of DTI characteristics in the gCC and PLIC after ETV. A: Delineation of ROIs in key white matter tracts. B: Preoperative FA color map of the patient at 25.6 months. C: Postoperative FA color map at 39.1 months. White arrows denote areas of the gCC and PLIC, with the most improvement in DTI characteristics following ETV. L ALIC = left ALIC; L PLIC = left PLIC; R ALIC = right ALIC; R PLIC = right PLIC.